O. pleuronectes. Pec. radiis 12 duplicatis, extus lævis.
O. obliterata. Pec. radiis 24 duplicatis, extus lævis.
O. radula. Pec. radiis 6 convexis decussate striatis, margine crenato, auriculis æqualibus.
O. plica. Pec. radiis 16 convexis læviusculis, decussato-striatus.
No specific name was appended to either this, the next, or the two preceding species.
O. pallium. Pec. radiis 12 convexis, striatus, scaber, squamis imbricatus.
This with the remainder of the Pectens (as far as flavicans) formed a group characterized by "Auricula altera intus ciliato-spinosa."
O. nodosa. Pec. radiis 9 nodoso-vesicularibus.
O. pes-felis. Pec. radiis 9, lævis, fornice squamis fornicatis.
The printed diagnosis, or heading, was evidently drawn up from a different shell.